A Food Allergy is an adverse reaction to food because of the body's immune response to a specific protein found in that food. Reactions can occur minutes to hours after ingestion, and can result in hives, itching or swelling in the mouth or throat, coughing, wheezing, and difficulty breathing, dizziness, weakness, and irregular heart rate, gastrointestinal symptoms such as pain, nausea, and vomiting, or life-threatening anaphylaxis. With a food allergy, even a microscopic amount of food can result in an immune reaction that could be serious, or even fatal.
A Food Intolerance involves the digestive system and may result in bloating, abdominal pain, or diarrhea. The immune system is not involved and though inconvenient, a food intolerance is not likely to be acutely life threatening. If a food tolerance is suspected, eliminating that food for several days can help you to determine if you need to avoid or limit consumption of the food.